Hibernation is a useful power management feature that's often sadly ignored despite its great benefits. When you hibernate a laptop, you’re essentially turning it off. So, unlike Stand By (sleep) mode, a hibernated laptop isn’t using any battery power at all — that laptop is off!

The secret behind hibernation is that before you turn off the laptop, everything you're doing with the computer is saved. (The contents of memory are saved to the hard disk.) When the computer is turned on again, it recovers from hibernating by reloading all the saved information and restoring your laptop to exactly the same condition it was in before it was hibernated.

Briefly, hibernation works like this:

You activate the hibernation feature.

Hibernation is activated differently depending on how it's set up.

The laptop hums as everything in memory is saved to disk.

The laptop turns itself off.

It’s really and truly off: The battery isn’t being used, and it's safe to store the laptop or put it away until you need to use it again.

To recover from Hibernation mode, you turn the laptop on, although in some cases the laptop may recover from hibernation when you press a key or touch the mouse pad. You should try that trick first, before you punch the power button.

Obviously, hibernation plays a key role in prolonging your laptop's battery power. You should put your laptop into hibernation when you know that you won’t be using it for longer than a half-hour or so. Unlike when you put your laptop in Stand By mode, you can leave your lap